Electrically operated manual power tool

ABSTRACT

A rotatable member is journalled for eccentric rotation in a housing, at the exterior of which it is accessible. A tool is provided having at least a stationary component and a movable component which can move relative to the stationary component and is provided with a slot. A projection rotates with the rotatable member and extends into the slot so as to impart periodic movement to the movable component. A mounting face of the housing is located in the plane of movement of the projection, and connecting screws connect the stationary component of the tool to this mounting face.

Paule et al.

[ Dec. 17, 1974 ELECTRICALLY OPERATED MANUAL POWER TOOL Inventors: Kurt Paule, Stuttgart; Giinter Zilly,

Oberaichen; Willy Reiss, Uhingen, all of Germany Robert Bosch G.m.b.H., Stuttgart,

Assignee:

Germany Filed: June 27, 1973 App]. No.: 373,960

Foreign Application Priority Data July 22, 1972 Germany 2236105 US. Cl. 30/220, 30/500, 74/571 R Int. Cl B26b 19/02 Field of Search 30/210, 220, 216, 228,

2,731,721 l/1956 Traurig.... 30/228 3,431,647 3/1969 Scott 30/210 3,585,719 10/1967 Kivela 30/500 X 3,623,223 11/1971 Edgell 30/220 3,747,594 7/1973 Bishop 30/228 X Primary Examiner-Al Lawrence Smith Assistant Examiner-4. C. Peters Attorney, Agent, or Firm-Michael S. Striker [57] ABSTRACT A rotatable member is journalled for eccentric rotation in a housing, at the exterior of which it is accessible. A tool is provided having at least a stationary component and a movable component which can move relative to the stationary component and is provided with a slot. A projection rotates with the rotatable member and extends into the slot so as to impart periodic movement to the movable component. A mounting face of the housing is located in the plane of movement of the projection, and connecting screws connect the stationary component of the tool to this mounting face.

5 Claims, 2 Drawing Figures ELECTRICALLY OPERATED MANUAL POWER TOOL BACKGROUND OF THE INVENTION The present invention relates generally to a manual tool, and more particularly to an electrically operated manual power tool.

It is already known to provide drive units for power tools, and particularly for hedge shears, grass shears and the like, where the particular tool i.e., the shear is fixedly connected with the drive unit. The modern trend is toward more and more of such powered usually electrically powered manually held tools, but because the tool and the drive unit are inseparable in ordinary use, each tool purchased will have its own drive unit and, in consequence the purchaser will have to pay as many drive units as he obtains tools. Moreover, ifv the tool itself needs repair or refurbishing, for instance if a grass shear is involved which needs to be sharpened, this cannot be done by the user, that is by having the user separate the grass shear and either sharpen it himself or take it to a place where it can be sharpened. Instead, he must take the entire tool including the power unit or drive unit therefor.

Evidently this is undesirable for various reasons, including questions of economy, excessive use of raw materials, for producing many power units where one power unit could several tools, as well as in terms of inconvenience for the user.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide an improved tool of the type under discussion which avoids the disadvantages of the prior art.

More particularly, it is an object to provide such an improved tool which has a drive unit to which different types of cutting tools can be readily attached and from which they can be equally readily detached.

Another object of the invention is to provide such a tool which makes it possible to accommodate the operation of the drive unit to different operating conditions of the various tools which can be connected with it.

A further object of the invention is to provide such a tool wherein such an accommodation can be carried out readily and wherein errors in the association of a particular tool with the drive unit are reliably precluded.

In keeping with these objects and others which will become apparent hereafter, one feature of the invention resides in an electrically operated manual power tool having a combination which comprises a housing and a rotatable member journalled for eccentric rotation relative to the housing and accessible exteriorly of the latter. A tool is mountable on the housing and comprises at least a stationary component, and at least a movable component connected with and movable relative to the stationary component and being provided with a slot. A projecting portion is fixed with the rotatable member for movement therewith and extends into the slot so as to impart periodic movement to the movable component. A mounting face is located in the plane of movement of the projecting portion, and connecting means connect the stationary component to this mounting face.

It is advantageous if the rotatable member is provided with one or more tapped bores, and if the pro jecting portion is provided with screw threads so that it can be threaded into the respective bore. If more than one bore is provided it is advantageous if they have different degrees of eccentricity with respect to the axis of rotation of the rotatable member, and the projecting portion can then be threaded into whichever one of these bores is selected, making it possible to accommodate the arrangement to the particular tool to be operated. In other words, it is now possible to select the operating stroke of a particular tool which is connected with the drive unit, merely by threading the projecting portion into an appropriately selected one of the bores.

The bores may also be of different diameters, and the projecting portion may be configurated so as to be threadedly engageable in one of the bores, with additional projecting portions being provided whose diameter is accommodated to other ones of the bores. The different tools will then have differently dimensioned slots, each dimensioned to cooperate with only one of the various projecting portions, which makes it possible to appropriately select the cooperating portion and tool merelyby a rapid visual comparison without having to carry out any measurements. The tools, usually cutting tools, which can be connected with and disconnected from the drive unit are advantageously so constructed that each constitutes a unit the component parts of which cannot unintentionally or accidentally become separated from one another.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side-elevational view, partly in section, il-

lustrating an embodiment of the present invention with DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing in detail, and firstly FIG. 1 thereof, it will be seen that reference numeral 1 identifies a housing which accommodates a non-illustrated electro-motor of conventional type, together with an output gear train which is driven by the electromotor and which is also not illustrated, being conventional. The gear train drives a rotatable member 2 which rotates about the diagrammatically illustrated axis in eccentric fashion, and which is provided with a projecting portion 3 which is also eccentrically connected to the member 2. A handle 4 on the housing is provided with a power cable 5 for supplying electrical energy to the electromotor, and with a switch 6 which is appropriateIy connected in circuit with the cable and the electromotor and serves to supply energy to the latter, and to interrupt the supply of energy. These features are known from the art.

The drive unit of the tool is provided in the plane of movement of the projecting portion 3, which latter of course rotates with the rotatable member 2, with a mounting face 9, having in the illustrated embodiment a plurality of tapped bores 10. A cutting tool, for instance a grass shears 13 can be connected to the mounting face 9 by means of screws 12, as shown in FIG. 1.

The drawing shows that in conventional manner, the cutting shears 2 comprise a stationary. component 14 and at least one (in the illustrated embodiment two) movable components 15. The latter have a bolt 17 which is provided with a bore 18 and a head 19 which serves as a fixed pivot. The bolt 17 passes through the stationary component 14 and the respective ones of the components and is connected to the mounting face 9 by means of one of the screws 12. A cover 20 is located between the face 9 and the bolt 17, the length of which latter serves to determine the spacing between the stationary component 14 and the cover 20. At the other points where the shears 13 are connected with the mounting face 9, an intermediate portion 12a is located between the stationary component 14 and the cover 20, being fixedly connected with them and being penetrated by the respective mounting screw 12. The latter have small discs fixed on their respective shafts and located in the depressions 23, the purpose being to prevent the screws 12 from unintentionally or accidentally becoming separated from the components 14 and 15, so that the latter will always be connected as a unit.

Each of the components 15 is provided with an elongated slot which extends in radial direction to the pivot point and into which the projecting portion 3 extends. The latter has a threaded section 27, a hexagonal section 28 by means of which the projecting portion 3 can be threaded into an appropriate bore of the rotatable member 2, and a cylindrical section 29 which is fittingly received in the slots 25, as illustrated. The cylindrical section 3 can of course also be smaller than the smaller dimension of the respective slots, contrary to what is shown in FIG. 2, in which case it can be surrounded by a glide sleeve 30 which is so dimensioned that its outer dimension corresponds to the smaller inner dimensions of the respective slot 25.

FIG. 1 shows that in the illustrated embodiment the rotatable member 2 is provided with two tapped bores 31 having different eccentricity relative to the axis of rotation of the member 2, as well as having different diameters. The number of such bores could of course be smaller or greater than two. Each of these bores has associated with it an appropriately dimensioned projecting portion 3 (only one shown in FIG. I), the cylindrical section of which is dimensioned so as to be fittingly received in only one slot of a single type of tool. For instance, it might be fittingly received in the slot 25 of a grass shears, such as the grass shears 13 shown in FIG. 1, but not in a similar slot of a hedge shears, as will be discussed with reference to FIG. 2. This makes it possible to select the appropriate eccentricity (and, therefore, the appropriate operating stroke of a particular tool which is connected with the face 9) without requiring any special considerations and without permitting the possibility of errors to occur during assembly.

Coming to FIG. 2 it will be seen that this illustrates the same construction as shown in FIG. ll, except that the grass shears 13 has been replaced with hedge shears 32. The latter also utilize a stationary component 14 and a movable component 15'. The hedge shears 32 are secured to the mounting face 9 by means of screws 12', as illustrated. The movable component 15' is located between and guided by a stationary component 14- and a cover 20'. The movable component 15' is further guided by not only the stationary component 14 but by an additional stationary component 37. The latter two stationary components are pressed against a distance or spacing rings located between them by means of screws 36, and are thus connected with one another. The rings 38 are each fittingly received in a slot 35 in the movable component 15' so that the latter can only perform a reciprocatory movement. A further elongated slot 25' extends normal to the reciprocatory movement of the movable component 15, and into the slot 25' extends the projecting portion 3' which is threaded into a tapped bore of the rotatable member 2 as shown and described with reference to FIG. 1.

It will be appreciated that when the projecting portion 3 performs movement in an orbital path, as a result of rotation of the member 2, the movable component 15' is made to reciprocate by an extent corresponding to the eccentricity of the projecting portion 3 with respect to the axis of rotation of the member 2'. The screws 12 again have the discs 22', as in FIG. I and for the same reasons described in that Figure. In all other respects, FIG. 2 corresponds to FIG. 1, since it is the same embodiment.

While we have described only the use of two different types of cutting tools, namely the grass shears l3 and the hedge shears 32, it will be appreciated that any other type of cutting tool can be employed, as long as it depends for its operation upon a movement which can be imparted to it by an eccentric projecting portion which slides in an elongated slot.

Evidently, the present invention makes it possible to use a single drive unit for operating various different types of cutting tools, and it further makes it possible to accommodate in a most simple manner the stroke of the motion-imparting projecting portion 3 or 3 to the particular cutting tool which is connected with the drive unit. The possibility of using projecting portions of different diameters, associated with tapped bores of different diameters, assures that even a person having no skill in the handling and assembling and disassembling of this type of equipment will be readily able to assemble a tool (such as the cutting tools) to the unit, and disassemble it therefrom, without making mistakes.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an electrically operated manual power tool, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. In an electrically operated manual power tool, a combination comprising a housing; a rotatable member journalled for eccentric rotation relative to said housing and accessible exteriorly of the latter, said rotatable member having a plurality of tapped bores of different diameters; a tool mountable on said housing and comprising at least one stationary component, and at least one movable component connected with and movable relative to said stationary component and provided with a slot; a plurality of projecting portions, all of said projecting portions being threaded and having different diameters so as to be usable only selectively and in conjunction with a corresponding particular one of said bores, one of said projecting portions being threaded into the corresponding particular one of said bores fixed with said rotatable member for movement therewith and extending into said slot so as to impart periodic movement to said movable component; a mounting face located in the plane of movement of said projecting portion; and connecting means for connecting said stationary component to said mounting face.

2. A combination as defined in claim 1, wherein said slot is dimensioned to accommodate one of said projecting portions; and further comprising at least one additional tool also having at least one stationary and at least one movable portion, the latter being provided with an additional slot dimensioned to accommodate only an other one of said projecting portions.

3. A combination as defined in claim 2, wherein one of said tools is a grass shears and an other one of said tools is a hedge shears.

4. A. combination as defined in claim 1, wherein said connecting means connects said components together so that they form an assembly incapable of accidental separation.

5. A combination as defined in claim 4, wherein said connecting means comprises screws extending through said components and having a head located adjacent one of said components and a retaining portion located adjacent the other of said components. 

1. In an electrically operated manual power tool, a combination comprising a housing; a rotatable member journalled for eccentric rotation relative to said housing and accessible exteriorly of the latter, said rotatable member having a plurality of tapped bores of different diameters; a tool mountable on said housing and comprising at least one stationary component, and at least one movable component connected with and movable relative to said stationary component and provided with a slot; a plurality of projecting portions, all of said projecting portions being threaded and having different diameters so as to be usable only selectively and in conjunction with a corresponding particular one of said bores, one of said projecting portions being threaded into the corresponding particular one of said bores fixed with said rotatable member for movement therewith and extending into said slot so as to impart periodic movement to said movable component; a mounting face locAted in the plane of movement of said projecting portion; and connecting means for connecting said stationary component to said mounting face.
 2. A combination as defined in claim 1, wherein said slot is dimensioned to accommodate one of said projecting portions; and further comprising at least one additional tool also having at least one stationary and at least one movable portion, the latter being provided with an additional slot dimensioned to accommodate only an other one of said projecting portions.
 3. A combination as defined in claim 2, wherein one of said tools is a grass shears and an other one of said tools is a hedge shears.
 4. A combination as defined in claim 1, wherein said connecting means connects said components together so that they form an assembly incapable of accidental separation.
 5. A combination as defined in claim 4, wherein said connecting means comprises screws extending through said components and having a head located adjacent one of said components and a retaining portion located adjacent the other of said components. 